TWI677696B - Method for radar target estimation - Google Patents

Abstract

The present invention provides a method for radar to estimate the target position, which includes the following steps in order: (a) establishing a radar scanning model, including: (a1) selecting an antenna field pattern; (a2) setting a radar parameter; (a3) Generate an echo simulation curve; (a4) Perform a sampling operation on the echo simulation curve to generate a plurality of simulation samples; (a5) Perform a normalization operation on each of the plurality of simulation samples to generate a plurality of Normalize simulation data. (b) Acquire a normalized scan data. (c) Perform a comparison operation between the plurality of normalized simulation data and the normalized scan data. And (d) obtaining a target bearing.

Description

Method for radar target estimation

The present invention relates to a method for estimating the target position of a radar, and more particularly to a method for estimating the target position of a rotary pulse wave Doppler radar.

Radar (Radar Detection and Ranging, RADAR) is a technology that detects the distance, bearing, height, and speed of an object by transmitting an electromagnetic wave signal and obtaining an object's reflected wave corresponding to the electromagnetic wave signal. Originally flourishing for military use, radar has been widely used in aviation, meteorology, telemetry, and even vehicle assisted driving.

Among them, Doppler radar is a technology that uses the Doppler effect to detect the speed of objects. Firstly, Doppler radar transmits electromagnetic waves to objects at a certain distance, and then performs spectrum analysis to analyze the frequency and phase of the reflected wave signal to detect The moving speed of the object, and the pulse wave Doppler radar uses multiple sets of coherent pulse wave technology, combining the characteristics of pulse wave radar and Doppler radar, and has excellent anti-clutter ability and accurate speed measurement ability. .

Different from the monopulse radar architecture, the traditional azimuth rotation radar method to estimate the target's position requires two or more stable and continuous echo signals to perform the estimation operation. When the target object's radar When the cross-sectional area (RCS) changes with its relative movement with the radar, the signal-to-noise ratio (SNR or S / N) of some echo signals is too small to be identified, Accurate bearing estimation based on this method The degree cannot be improved, and even if the pulse Doppler radar can increase the signal-to-clutter ratio (SCR or S / C), it still faces the same problem.

In order to solve the problems mentioned in the prior art, the present invention provides a method for radar to estimate the target position, which includes sequentially performing the following steps: a. Establishing a radar scanning model, including: a1. Selecting an antenna field shape A2. Set a radar parameter; a3. Generate an echo simulation curve; a4. Perform a sampling operation on this echo simulation curve to generate a plurality of simulation samples; a5. Perform a normalization on each of the plurality of simulation samples Action to generate a plurality of normalized simulation data; b. Obtain a normalized scan data; c. Perform a comparison operation on the plurality of normalized simulation data and the normalized scan data; and d. Obtain a target orientation.

The method for estimating the target position of the radar of the present invention only needs to estimate the target position within a set of coherent processing intervals. Its accuracy is not easily affected by background clutter, and the radar search resources are limited. In this case, or in the case where multiple sets of coherent pulses are continuously emitted and the target has only one set of effective detection, a highly accurate target position estimation can still be obtained.

The above brief description of this creation aims to make a basic explanation of several aspects and technical characteristics of this creation. The creation brief is not a detailed description of the creation, so its purpose is not special The enumeration of the key or important elements of this creation is not intended to define the scope of this creation, but merely to present several concepts of this creation in a concise manner.

100‧‧‧ Antenna Field Pattern

200‧‧‧beam shape loss

201‧‧‧ target echo signal

300‧‧‧ goals

301‧‧‧actual target position

a ~ d‧‧‧step

a1 ~ a5‧‧‧step

f1 ~ i‧‧‧step

e2 ~ i‧‧‧step

(Figure 1) Schematic diagram of the method for estimating the target position of the radar by the embodiment of the present invention; (Figure 2) Schematic flowchart of the method of estimating the target position of the radar by the embodiment of the present invention; (Figure 3) the radar of the embodiment of the present invention A schematic diagram of the antenna field type of the method for estimating the target position; (FIG. 4) A schematic flowchart of a method for estimating the target position of the radar according to another embodiment of the present invention.

In order to understand the technical features and practical effects of the present invention, and can be implemented in accordance with the contents of the description, the preferred embodiment shown in the drawings is further described in detail below.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a method for estimating a target position by a radar according to an embodiment of the present invention. In this embodiment, a scanning radar transmits a set of a scanning signal composed of a plurality of coherent pulses in space, and obtains an echo signal corresponding to the scanning signal, and uses the echo signal to transmit and receive signals. The beam shape is lost 200 to detect the actual target orientation 301 of the target 300. Specifically, the flow of this step includes sequentially performing the following steps: In step b1, a scanning radar transmits a set of scanning signals composed of a plurality of coherent pulse waves. In step b2, a target echo signal 201 corresponding to one of the scan signals is obtained. In step b3, a weight operation is performed on the target echo signal 201 to obtain a weighted echo signal. In step b4, a Fourier transform operation is performed on the weighted echo signal to obtain a radar scan data. In step b5, a target detection operation is performed on the radar scan data to extract a target spectrum data. In step b5, an inverse Fourier transform operation is performed on the target spectrum data to generate a scan sample. In step b7, a normalization operation is performed on the scan sample to generate normalized scan data.

Please refer to FIG. 2, which is a schematic flowchart of a method for estimating a target position of a radar according to an embodiment of the present invention. It can be seen from FIG. 2 that the method for estimating the target position of the radar in this embodiment includes performing the following steps in order: step a, in step a, establishing a radar scanning model, including: step a1, selecting an antenna field pattern State 100; step a2, setting a radar parameter; step a3, generating an echo simulation curve; step a4, performing a sampling operation on the echo simulation curve to generate a plurality of simulation samples; step a5, for each of the plurality of The simulation sample performs a normalization operation to generate a plurality of normalized simulation data. In step b, a normalized scan data is acquired. In step c, a comparison operation is performed on the plurality of normalized simulation data and the normalized scan data. And step d, in step d, obtain an estimated target orientation.

Please refer to FIG. 2 and FIG. 3 at the same time. FIG. 3 is a schematic diagram of an antenna field type of a method for radar target estimation by an embodiment of the present invention. The method for estimating the target position of a radar according to the present invention includes the following steps: First, execute step a to establish a radar scanning model, including: selecting an antenna field shape in step a1. In this embodiment, the antenna field pattern uses an approximate field pattern with a Gaussian distribution. In other possible embodiments, the antenna field pattern may also be selected from an antenna field pattern obtained by actual measurement in a microwave dark room, an ideal antenna field pattern simulated by a sinc function, and an approximate half of a parabolic function. Power (3dB) field type. Next, in step a2, a radar parameter is set, and the antenna speed in this set of parameters is the scanning speed of the scanning radar. The antenna of the scanning radar is fixed on a base, and the base provides continuous rotation of the antenna azimuth. A weighting function is used to suppress the side wave gain in the frequency spectrum. The weighting function can be selected from one of Hamming Window, Hanning Window, Chebyshev Window and Without Weighting. In step a3, an echo simulation curve is generated. The echo simulation curve is an ideal reflection wave signal obtained after the scanning signal of the target 300 reflection scanning radar. In step a4, a sampling operation is performed on the echo simulation curve to generate a plurality of simulation samples. Then, the plurality of simulation samples are individually weighted to generate a plurality of weight simulations. sample. Finally, in step a5, a normalization operation is performed on each of the plurality of weighted simulation samples to generate a plurality of normalized simulation data. In a preferred embodiment, the number of the plurality of normalized simulation data is M, where M is a value selected according to a system condition. Specifically, M is adjusted according to the performance of the radar data processor, radar parameters, and the fineness required for azimuth estimation.

Preferably, step a further includes setting a radar parameter after performing step a2, and then performing step a3. Specifically, this set of radar parameters also includes a pulse repetition interval (PRI). Therefore, after the antenna field pattern 100 is established, the antenna speed and pulse repetition interval parameters are then input. An echo simulation curve can be generated.

-N；其中θ為一半功率波寬(3dB波寬)、ω為天線轉速以及T為一脈波重覆間隔。 In an embodiment, each of the plurality of normalized simulation data and normalized scan data further includes a plurality of data, and the number of the plurality of data is N, and N is a power value of 2, such as 16, 32, 64, 256, etc., and this N value is exactly the number of samples of the Fourier transform action and the inverse Fourier transform action. In an embodiment, the target distance detected by the radar is greater than the range covered by the pulse wave repetition interval used by the radar, resulting in the number of detected coherent pulse waves of the target being less than N, and the normalized simulation is adjusted accordingly The number of data contained in the data and normalized scan data. In a preferred embodiment, after considering factors such as the processing performance of the computing system, the parameters of the scanning radar and scanning signals, and the fineness required for azimuth estimation, M has an optimal value, and the optimal value is

-N ; where θ is half the power wave width (3dB wave width), ω is the antenna speed, and T is a pulse wave repeat interval.

After obtaining the plurality of normalized simulation data and the normalized scan data, a comparison operation is performed on the plurality of normalized simulation data and the normalized scan data, and an estimated target position is obtained. This comparison action includes comparing the M normalized simulation data with the normalized scan data one by one. Specifically, the M normalized simulation data are M normalized segments in the echo simulation curve. In one embodiment, the comparison action includes the plurality of normalized simulation data. An inner product operation is performed with the normalized scan data, and a maximum value is taken out, and the angle at which the normalized simulation data with the large value is given corresponds to the actual target orientation 301. In another embodiment, the comparison action includes performing a norm operation of a vector difference between the plurality of normalized simulation data and the normalized scan data, and taking a minimum value to give a normalized simulation of the minimum value. The angle of the data corresponds to the actual target orientation 301.

Here, the sampling operation in step a4 and the normalization operation in step a5 will be further described. For example, in step a4, the echo simulation curve is sampled and generated: {a _i | i = 1, ..., n}, a total of n simulation samples. Continuing, taking 4 pieces of data (that is, N = 4) as a group, there can be a total of n-N + 1 groups (that is, M = n-N + 1) simulation samples: (S ₁ , S ₂ , S ₃ , S ₄ ), (S ₂ , S ₃ , S ₄ , S ₅ ) ... (S _n-3 , S _n-2 , S _n-1 , S _n ), and according to the weight function (W ₁ , W ₂ , W ₃ , W ₄ ) Perform weight calculation on the complex array simulation samples, and obtain (S ₁ W ₁ , S ₂ W ₂ , S ₃ W ₃ , S ₄ W ₄ ), (S ₂ W ₁ , _{S 3 W 2, S 4 W} 3, S 5 W 4) ... (S n-3 W 1, S n-2 W 2, S n-1 W 3, S n W 4) after co M set of weights analog For the sample, the normalization action of each group is performed for the M group of simulation samples, and normalized simulation data of a total of M groups can be obtained.

Preferably, the target echo signal 201 is a plurality of coherent echo signals obtained by the scanning radar in one scanning operation, which is different from the past that requires several scanning operations to obtain the target's position, so the radar resource allocation can be optimized. To provide more space search or additional target tracking capabilities.

Please refer to FIG. 1 and FIG. 4 at the same time. FIG. 4 is a schematic flowchart of a method for estimating a target position of a radar according to another embodiment of the present invention. As can be seen in Figure 4, the establishment of the radar scanning model requires the selection of an antenna field pattern (f1), input of antenna rotation speed, pulse wave repetition interval, and weight function to generate an echo simulation curve (g1) . Then, after sampling operation and normalization operation, M pieces of normalized simulation data (h1) with N pieces of data are obtained. On the other hand, a scanning radar transmits a set of scanning signals composed of a plurality of coherent pulses in space and obtains the corresponding signals. One of the scanning signals is the target echo signal 201 (e2). At this time, the resolver simultaneously records the scanning position of the current scanning radar. After the target echo signal 201 is processed by the pulse Doppler, the target is detected to obtain a target spectrum data (f2), and the target spectrum data is then subjected to an inverse Fourier transform operation to generate a scan sample (g2), where The scan sample also has N data, and after the scan sample is normalized, a normalized scan data (h2) with N data is generated. Finally, a comparison operation is performed between the M normalized simulation data with N data and a normalized scan data with N data to obtain an estimated target orientation correction angle. This correction angle corresponds to the scanning signal. The scan position is added to obtain the target position to correspond to the actual target position 301 (i).

The method for estimating the target position of the radar of the present invention only needs to perform a scanning operation to detect the target position, and its accuracy is not limited by the background clutter of the reflected wave signal, with fewer radar resources and systems. Resources to achieve a highly accurate target orientation estimation. In one embodiment, when multiple sets of coherent pulses are continuously transmitted and the target has only one set of effective detection, a highly accurate target position estimation can still be obtained. However, the above are only the preferred embodiments of the present invention. When the scope of implementation of the present invention cannot be limited by this, that is, the simple equivalent changes and modifications made in accordance with the scope of the patent application and the description of the present invention are still It is within the scope of the present invention.

Claims (9)

A method for radar estimation of target position includes performing the following steps in order: a. Establishing a radar scanning model, including: a1. Selecting an antenna field type; a2. Setting a radar parameter; a3. Generating an echo simulation A4. Perform a sampling operation on the echo simulation curve to generate a plurality of simulation samples; a5. Perform a normalization operation on each of the plurality of simulation samples to generate a plurality of normalized simulation data; b. Obtain a normal Scanning data includes: b1. A scanning radar transmits a set of scanning signals composed of a plurality of coherent pulses; b2. Obtaining a target echo signal corresponding to the scanning signal; b3. Performing a target echo signal A weight calculation to obtain a weighted echo signal; b4. Perform a Fourier transform operation on the weighted echo signal to obtain a radar scan data; b5. Perform a target detection operation on the radar scan data to take out a target Spectrum data; b6. Performing an inverse Fourier transform operation on the target spectrum data to generate a scan sample; and b7. Performing the normalization operation on the scan sample to generate the normalized scan Data; c. Performing a comparison operation between the plurality of normalized simulation data and the normalized scan data; and d. Obtaining a target orientation. The method of radar target estimation according to claim 1, wherein the number of the plurality of normalized simulation data is M, where M is a value selected according to a system condition. The method for estimating the target position of a radar according to claim 1, wherein the target echo signal is a plurality of coherent echo signals of the scanning radar during a scanning operation. The method for estimating the target position of a radar according to claim 2, wherein each of the plurality of normalized simulation data and the normalized scan data further includes a plurality of data, and the number of the plurality of data is less than or equal to N, and N is A power of two. The method for estimating the target position of a radar according to claim 1, wherein the radar parameters include an antenna rotation speed, a pulse wave repetition interval, and a weight function. The method for estimating the target position of a radar according to claim 1, wherein step a further comprises performing a weight operation on each of the plurality of simulation samples after performing step a4, and then performing step a5. The method for radar target estimation according to claim 2, wherein M is an optimal value, and the optimal value is -N ; where θ is half the power wave width, ω is the speed of the antenna, and T is a set of pulse wave repeat intervals. The method for estimating the target position of a radar according to claim 1, wherein the comparison action includes; performing a inner product operation between the plurality of normalized simulation data and the normalized scan data, and extracting a maximum value. The method for estimating the target position of a radar according to claim 1, wherein the comparison action includes: performing a norm operation of a vector difference between the plurality of normalized simulation data and the normalized scan data, and extracting a minimum value. .